import 'package:flutter/material.dart';
import 'package:english_words/english_words.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Startup Name Generator',
      theme: new ThemeData(
        // Add the 3 lines from here...
        primaryColor: Colors.deepPurple,
      ), // ... to here.
      home: RandomWords(),
    );
  }
}

class RandomWordsState extends State<RandomWords> {
  final _suggestions = <WordPair>[];
  final Set<WordPair> _saved = new Set<WordPair>();
  final _biggerFont = const TextStyle(fontSize: 18.0);

  Widget _buildSuggestions() {
    return ListView.builder(
        padding: const EdgeInsets.all(16.0),

        // and places each suggestion into a ListTile row.
        // For even rows, the function adds a ListTile row for the word pairing.
        // For odd rows, the function adds a Divider widget to visually
        // separate the entries. Note that the divider may be difficult
        // to see on smaller devices.
        itemBuilder: (context, i) {
          // Add a one-pixel-high divider widget before each row in theListView.
          if (i.isOdd) return Divider();

          // The syntax "i ~/ 2" divides i by 2 and returns an integer result.
          // For example: 1, 2, 3, 4, 5 becomes 0, 1, 1, 2, 2.
          // This calculates the actual number of word pairings in the ListView,
          // minus the divider widgets.
          final index = i ~/ 2;
          // If you've reached the end of the available word pairings...
          if (index >= _suggestions.length) {
            // ...then generate 10 more and add them to the suggestions list.
            _suggestions.addAll(generateWordPairs().take(10));
          }
          return _buildRow(_suggestions[index]);
        });
  }

  Widget _buildRow(WordPair pair) {
    final bool alreadySaved = _saved.contains(pair);
    return ListTile(
      title: Text(
        pair.asPascalCase,
        style: _biggerFont,
      ),
      trailing: new Icon(
        // Add the lines from here...
        alreadySaved ? Icons.favorite : Icons.favorite_border,
        color: alreadySaved ? Colors.red : null,
      ), // ... to here.
      onTap: () {
        // Add 9 lines from here...
        setState(() {
          if (alreadySaved) {
            _saved.remove(pair);
          } else {
            _saved.add(pair);
          }
        });
      }, // ... to here.
    );
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Startup Name Generator'),
        actions: <Widget>[
          // Add 3 lines from here...
          new IconButton(icon: const Icon(Icons.list), onPressed: _pushSaved),
        ],
      ),
      body: _buildSuggestions(),
    );
  }

  void _pushSaved() {
    Navigator.of(context).push(
      new MaterialPageRoute<void>(
        builder: (BuildContext context) {
          final Iterable<ListTile> tiles = _saved.map(
            (WordPair pair) {
              return new ListTile(
                title: new Text(
                  pair.asPascalCase,
                  style: _biggerFont,
                ),
              );
            },
          );
          final List<Widget> divided = ListTile.divideTiles(
            context: context,
            tiles: tiles,
          ).toList();

          return new Scaffold(
            // Add 6 lines from here...
            appBar: new AppBar(
              title: const Text('Saved Suggestions'),
            ),
            body: new ListView(children: divided),
          ); // ... to here.
        },
      ),
    );
  }
}

class RandomWords extends StatefulWidget {
  @override
  RandomWordsState createState() => new RandomWordsState();
}